The Environmental Protection Agency is tightening the air quality health standard for smog, but delayed the announcement, which had been scheduled for 1 p.m.
The EPA must set new ozone standards by Thursday to comply with a court order.
Officials and lobbyists said the EPA had told them earlier Wednesday that it was ready to announce a tightening of the federal ozone, or smog, standard to 75 parts per billion. Many more counties would not meet this standard, including Bibb County, where air quality had improved just enough for the county to be removed from "non-attainment" status last year.
Georgia environmental officials, Gov. Sonny Perdue, Georgia Senator Saxby Chambliss and Georgia business groups had all argued against the EPA tightening the standard. Even so, the new standard would still be less stringent than what health experts have said is needed to protect children and the elderly and prevent hundreds of premature deaths.
Ground-level ozone, the primary component of smog, causes breathing problems and has been linked to heart- and lung-related deaths.